Subterranean reservoirs may change over time due to various conditions including geological issues and treatments performed relative to the reservoir. Such changes may impact the reservoir and the surrounding formation. For example, hydrocarbon recovery treatments may be enhanced by injecting water or steam into a reservoir. In such instances, it may be useful to monitor injection of water or steam, as well as other fluids into a subterranean formation, and/or to monitor progress of such fluids toward or away from one or more wellbores in the reservoir.